Preheat the oven to 350 degrees. Place a baking rack into a rimmed baking sheet, or set a broiler rack in a broiler pan. You can also bake the potatoes directly on the rack inside your oven - just be sure to place a pan on the rack underneath the potatoes to catch any dripping oil.
Prick potatoes all over with a knife or a fork. This will allow steam to escape. If you skip this step, there's a pretty good change the potatoes will explode in your oven, which is no bueno. 🙂
Add the oil to a small bowl. Put each potato in the oil and use your hands to coat the skin completely with oil.
Place the potatoes on the rack inside the pan. Sprinkle the potatoes with salt, turning them over as you do to coat all sides.
Roast until they feel very tender if you poke a fork into one of them, about 60–90 minutes.